Answer:
Because Pangaea has started 200 million years ago
Explanation.
In the proposal, they stated that they want to study the sediments before the break of Pangaea , the break of pangaea began 200 million years ago, the process and method of study is dependent on the fact that Pangaea has not broken, but further reading , it is clear that it has started 200 million years ago, then obviously ,since the break has started 200 millions year ago, they must have had great impact on the sediments that the researcher wants to use to carry out the research.
The methodology is the error and that is why the proposed study is not possible as Pangaea as already started breaking since 200 million years ago.